Multi-spectral imaging techniques MAVRIC and SEMAC image acquisition techniques are currently being investigated for reduction of susceptibility artefacts due to the presence of metal.
The MAVRIC acquisition is not volume selective and MAVRIC will therefore suffer from back-folded signal if the encoded volume is too small. The slice selection used in SEMAC is a single frequency band selection in combination with a single selection gradient strength for both refocusing and excitation, which may cause distant off-resonance signals to be selected, resulting in back-folded signal.
In Koch et. al., “Multiple Resonant Frequency Offset Acquisitions for Imaging of Metallic Implants,” Magnetic Resonance in Medicine, volume 61, 2009, pp. 381-390, the MAVRIC imaging technique is explained.
In Lu et. al., “SEMAC: Slice Encoding for Metal Artifact Correction in MRI,” Magnetic Resonance in Medicine, volume 62, 2009, pp. 66-76, the SEMAC image acquisition technique is explained.
In C. Bos et al., ‘MR imaging near orthopedic implanted with artefact reduction using view-angle tilting and off-resonance suppression’, ISMRM 2010 abstract 1128, view angel tilting is explained.